It is common practice in painting and carrying out maintenance and repair work underneath bridges to install temporary work platforms under the bridge deck. One form of platform consists of horizontal cables attached to transversely opposite supporting columns of the bridge structure or to other available components of the bridge and corrugated decking panels supported by the cables. The decking panels are attached to the cables by clamp assemblies. Generally, each decking panel is attached adjacent each end to the cables that it spans by a clamping assembly. The decking panel has a hole at each end that overlies a segment of the support cable and that accepts a loop portion of either a U-bolt or a J-shaped bolt ("J-bolt"). The loop portion of the U-bolt or J-bolt is engaged under the cable. One leg of the U-or J-bolt is welded to a first clamp plate. The other leg is threaded and free, so that the free end can be maneuvered through the hole and under the cable from above the panel. A second clamp plate with a hole for the threaded leg is then placed on the free end of the bolt, and a nut is installed on the threaded end of the bolt and tightened to draw the loop portion of the U- or J-bolt into engagement with the cable and the two clamp plates down into engagement with portions of the upper surface of the deck adjacent the deck opening.
The previously known clamp assemblies are relatively complicated and costly to produce. They consist of three parts (the bolt and two plates) and require several cutting, drilling and welding steps to make them. Installation requires fishing the U- or J-bolt through the hole in the decking and under the cable and holding the U- or J-bolt/clamping plate unit in place while the other plate and the nut are installed. Removing the clamp plates involves the same steps as installation, in reverse order. In short, installation and removal of the previously known clamp plates are relatively tedious and time-consuming.
The temporary work platforms to which the present invention pertains sometimes include one or more vertical suspension cables, each of which is fastened at its upper end to an element, such as a cross beam, on the underside of the bridge deck and at its lower end to a transverse support cable. It has been previously known to provide for the connection of the lower end of the suspension cable by means of a ring or U-hook that is welded to a base plate, which, in turn, is bolted to the U-bolt of the clamp assembly above the clamp plates of the assembly and under the nuts. The ring or U-hook/base plate is yet another, separate component of the system, thus requiring costly fabrication and yet another installation step.